It is a close relative of Asplenium ruprechtii[2] (syn: Camptosorus sibiricus) which is found in East Asia and also goes by the common name of "walking fern".

[3] Asplenium rhizophyllum is a small fern whose undivided, evergreen leaves and long, narrow leaf tips, sometimes curving back and rooting, give it a highly distinctive appearance.

Its rhizomes (underground stems) are upright or nearly so,[2][5] short,[4] about 1 millimetre (0.04 in) in diameter,[5] and generally unbranched.

On rare occasions, the auricles at the leaf base will also take on an attenuate shape and form roots at the tip.

[2] The ability of the leaf tips to root and form a new plant at some distance from the parent gives the species its common name.

[6] The young leaves forming from a bud at the leaf tip are round to pointed at their apex, not yet having developed the long-attenuate shape.

[7] Fertile fronds bear a large number of sori underneath, 1 to 4 millimetres (0.04 to 0.2 in) long,[5] which are not arranged in any particular order.

An artificial backcross between A. rhizophyllum and A. tutwilerae was closer to A. rhizophyllum in morphology, but still remained some lobes in the basal part of the blade, had a shallowly undulating, rather than smoothly curved, leaf edge in the apical part, showed a maroon color in the stipe up to the base of the leaf blade, and possessed the abortive spores of a sterile hybrid.

[9] A. ruprechtii, the Asian walking fern, also possesses attenuate, proliferating tips, but has a lanceolate leaf blade, which tapers to a wedge at the base rather than forming a heart shape.

The first of these homonyms was created by Linnaeus himself in 1763, when he accidentally used the name twice, applying it first to his original taxon and again to a species from the West Indies which also proliferates at the leaf tips.

[22] A global phylogeny of Asplenium published in 2020 divided the genus into eleven clades,[23] which were given informal names pending further taxonomic study.

[25] There is no clear morphological feature that unites the A. cordatum subclade; the sister species of A. rhizophyllum is A. ruprechtii, which shares an undivided leaf blade and a proliferating tip, while the other three species are scaly spleenworts of dry habitats in Africa and the Middle East.

A similar plant collected from limestone in Shepherdstown, West Virginia could have originated from the same parents, from an unreduced (diploid) gametophyte of Scott's spleenwort crossed with walking fern, or from an unreduced walking fern gametophyte crossed with ebony spleenwort.

[33] In 1922, Ralph Hoffmann gave the name C. rhizophyllus f. auriculatus to specimens with proliferating auricles, based on material on limestone from New Marlborough, Massachusetts.

[34] In 1924, Frederick W. Gray described as C. rhizophyllus f. angustatus material from a sandstone boulder in Monroe County, West Virginia.

These plants had deeply lobed auricles, and erose (jagged or indented) leaf margins with rounded edges.

[38] The distribution typically follows area of limy soil;[4] sometimes said to be rare, it is better described as locally abundant where conditions favor it.

[41] It prefers low to medium light levels, and a moist, basic potting mix,[6][42] or soil with added lime chips.